Exchange coupling in CaMnO3and LaMnO3 : an ab initio study

Abstract

This thesis is a study of the magnetic properties of a class of compounds known as manganites. They possess many peculiar properties which make them an interesting field of investigation for both experimentalists and theoreticians. The present work deals in particular with CaMnO3 and LaMnO3, end-point compounds of the series LaxCa1-xMnO3. The main issues addressed are the explanation of the magnetic interactions between manganese ions and the calculation of the exchange coupling constants J. The aim is to provide some of the missing information which is still needed for a complete understanding of the microscopic origin of colossal magnetoresistance in mixed-valence manganites.